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CRAMP Study Sites: Hanauma Bay, Island of Oahu

Pupukea -- Waiāhole -- He‘eia Kea -- Moku O Loe -- Hanauma Bay -- Ala Wai -- Kahe Point -- Pili O Kahe

Geographic Name: Hanauma Bay

CRAMP Site Code: OaHan

Geographic Coordinates:

21° 16.113' N; 157° 41.700' W

21° 16.055' N; 157° 41.643' W

Aerial view of Hanauma Bay.

Chart showing Hanauma Bay. Red arrows indicate the location of transect sites.

Chart showing Hanauma Bay. Red arrows indicate the location of transect sites. (Click image for larger view.)

Management Status:

Hanauma Bay Marine Life Conservation District (MLCD), established in 1967, was the first MLCD in Hawai‘i.  Established to conserve and replenish marine resources, MLCDs provide fish and other marine life with a protected area in which they can grow and reproduce.  While state laws restrict the taking of all marine life within the Hanauma Bay MLCD, snorkeling, diving, underwater photography, and other similar passive activities are allowed. 

The Place Name Hanauma

Hanauma pronounced "ha now ma" is a Hawaiian word that can have several meanings. Originally, the Hawaiian language was not a written language. It was passed down orally through song, dance, stories and legends from one generation to the next. This oral transmission resulted in some changes and loss of place names. Place names frequently described a salient landmark or feature or may describe an important historical event.

In place names, hana refers to a bay or valley. Uma can have multiple meanings:

  • 1) Uma can refer to a curve, as in the natural geological formation of the crescent shape of the bay.

  • 2) Another meaning refers to the sport of hand-wrestling, uma, where opponents knelt with elbows on the ground and right hands locked together and tried to force the other down. Hanauma Bay was known as a place where ali‘i the ruling class would gather to play uma as well as other recreational activities.

  • 3) The stern of a canoe is also known by the term uma. Traditional Hawaiian navigators would ride a strong current across the Ka‘iwi Channel from Ilio Point on Moloka‘i to Hanauma Bay with relatively little effort.

Thus, three suggested meanings for Hanauma Bay are: curved bay, hand-wrestling bay, canoe stern bay (Name origin dictionary of Hawaiian localities-Pukui).

Historical Background:

Hanauma Bay was known as a favorite fishing spot for ali‘i, Hawaiian royalty. King Kamehameha V used the bay often for fishing. Queen Ka‘ahumanu would visited for a month at a time. Hula dancers entertained the ali‘i and sports and games were enjoyed there.

When sailing canoes inter-island from O‘ahu to Moloka‘i, Hawaiians would often use Hanauma Bay as a stop over in the voyage from Honolulu on O‘ahu to Moloka‘i. In times of foul weather or high winds since the Ka‘iwi or Moloka‘i Channel can be one of the roughest in the world, this served as a safe refuge until fairer weather conditions prevailed. The navigator would climb to Kuamo‘o o Kane, the ridge on the west side of Hanauma to assess the strength and direction of the winds.

Historic Events:

Hanauma Bay was designated a Marine Life Conservation District (MLCD) in 1967. This is an area that the State of Hawai‘i set aside to protect marine life. It is governed by State statutes, Regulation 32. It states that it is unlawful to fish, possess fishing gear, remove any marine organisms or contaminate the waters within the conservation district. This law is enforced by the Department of Land and Natural Resources.

Prior to 1967, most types of fishing was allowed in the bay. It was a popular fishing and camp grounds for people from Honolulu. By the 1960’s fish stocks began to decline from the heavy fishing pressure. A University of Hawai‘i marine biologist, Dr. Ernst Reese had proposed that the bay be set aside as a natural, living museum. Many fishermen protested this idea for fear of setting a precedent to close other traditional fishing grounds. An underwater survey was conducted by Chapman Lam and the data gathered was used to convince the State Legislature to designate the site as a MLCD.


Many legends were told of Hanauma Bay. Legends were often expressed in the form of traditional songs, chants and dance. One love story recants the tale of two very powerful ali‘i or chiefs. They were both experts in the sport of uma or hand-wrestling. This sport tested the strength of the participants by locking hands and forcing the opponent to the ground.

Ali‘i Koko (blood) and Ali‘i Hana (work, act) both fell deeply in love with the most beautiful maiden in Hawai‘i, Keohinani. Her father was the guardian of Hanauma Bay, Keanamo‘o, the great lizard. Her hand in marriage was to be decided by a contest of strength and perseverance to determine their nobility. All day the two men struggled to prove their greatness yet each was equally strong. As the twilight began to fall the score remained even in match after match.

Keohinani loved both men and it pained her to see their suffering and loss of dignity. As the contest continued she climbed to the top of the crater. As she climbed, ascending closer to the gods she called to the akua. "Transform me into a hill so the pain and suffering will be over". Instantly, she was transformed into part of the crater, to the hill today called "fair mountain", Kohelepelepe, where the modern day radar station stands. Her unselfish deed allowed her suitors to gaze with awe upon her beauty and innocence forever.

Her father, deeply moved and pleased by his daughter’s humble act of kindness transformed himself into the crater rim above her that encircles Hanauma Bay. These two inter-twined ridges remind us today of the locked arms of the sport of uma that gave rise to the crater rims of Hanauma Bay.


In 1931 a Bishop Museum survey was conducted by J.G. McAllister. Several sites were identified and relocated.

Site 44: Located on the Sandy Beach side of "toilet bowl" this cave contained several petroglyphs

Site 45: Located on Kohelepelepe Ridge is a platform not located at this time

Site 46: Located near the waters edge this is a stone fishing shrine

Site 47 and 48: Located on the Honolulu side of Koko Head are two fishing shrines, each about 17 feet square

Site 49: Kuapa or Keahupua o Maunalua fishpond recorded by Webster in 1851 as 523 acres in size. Recorded by Mathison in 1922 as having a village of 100 huts on the shores of the fishpond.

In 1952, a cave below the cliff of Hanauma Bay was excavated by Dr. Kenneth Emory of the University of Hawai‘i. Approximately 210 sq. ft. of the Hanauma Shelter Cave (Site 80-15-03) was excavated. Fishing-related artifacts indicated use of the cave by early Hawaiians as a temporary shelter while fishing and collecting from the Bay. This shelter was placed on the Hawai‘i Register of Historic Places in 1971.

In 1980, Robert D. Connolly was commissioned by the City and County of Honolulu to conduct a archaeological reconnaissance survey of the beach park. No prehistoric cultural remains were found within the beach area.

Geology of Hanauma Bay

Hanauma Bay is part of the Ko‘olau mountain range that was formed on the east side of the island of O‘ahu. Subsequent to the end of the volcanic activity that formed the main range, the north-east side of the crater collapsed and fell into the sea, leaving the Pali cliff-line as evidence of this giant landslide. After the eruptions that formed the Ko‘olaus there was a period of volcanic quiet lasting for at least two million years.

More than 30 separate eruptions flowed out over the eroded landscape and onto the fringing reef about half a million years ago when rejuvenation-stage volcanism occurred. This "Honolulu Series" of flows gave rise to many salient geologic features on O‘ahu including Diamond Head, Punchbowl and Hanauma Bay.

The flows that formed the craters of Hanauma Bay began about 40,000 years ago. Hanauma Bay is a compound crater formed by at least six separate cones. The Hanauma Bay craters are nested in another earlier crater. One of the latest stages of volcanics includes the Koko Crater. Nine eruptions along the Koko fissure occurred over the next several thousand years following the initial outbreaks of these late stage eruptions. The cratered cones of Hanauma Bay were built by hydromagmatic explosion of the Surtseyan type. The open vent was underwater and as a result of contact with the water, the magma was finely fragmented resulting in the predominately ash cones. This type of explosion produces fine ash that settles onto land, and due to the chemical reaction of the material becomes firmly cemented in place. This hardened ash is refereed to as tuff, forming the tuff cones of Hanauma Bay. These violent explosions blasted through a previously established coral reef. White fragments of limestone imbedded within the consolidated ash from the underlying reef can be seen in the walls of tuff today. Research indicates the formation of the reef approximately 32,000 years ago. Black basaltic fragments and olivine crystals can also be seen in the crater walls and the sands of the bay. A olivine beach is evident in the "Toilet Bowl" section of the bench. The mineral olivine is found in areas of geologically recent volcanic activity.

Sea cliffs were formed from erosion of the crater walls of Hanauma Bay. The sea cliffs of the bay were formed as extensive wave action and weathering undercut the tuff causing large areas to fall into the sea or on the underlying bench below. This bench developed below the cliffs and ranges from 1- to 6 meters above sea level. This coastal bench formation was exposed to wave action. The waves protected the bench from desiccation. Salt weathering was the major factor in the retreat of the cliff wall. Thus the bench formed as a result of the retreat and degradation of the adjacent cliff rather than from the exposure to waves.

Hanauma Bay is diverse in marine habitats. Tidepools are evident in shallow waters at the reef edge. The reef at Hanauma Bay is a fringing reef, one that grows along the shoreline. As elsewhere in Hawai‘i, the greatest contributor to the reefs are calcareous red algae that secrete a hard material cementing accreted substances to the underlying substrate. The back reef area is located near the sandy beach and is composed largely of sand or coral rubble. This reef flat has been extensively modified by anthropogenic activity. Photographs by Chester K. Wentworth depicting the coral cover in 1926 are evidence of the decline in coral cover on the inner reef flat. The fore reef or reef front protects the beach from erosion by absorbing most of the wave energy. A spur and groove region creates channels to further dissipate the wave force. The deeper reefs with more extensive coral cover extend out to the mouth of the bay to 30 meter depths.

Historical Timeline and Photos of Hanauma Bay:

Located within Koko Head Park, the 100 acre Hanauma Bay marine life conservation district attracts 1.2 million visitors annually. In 1977 a survey revealed 68% of park users were kama‘aina, residents of O‘ahu. By 1988, that number had dropped to less than 30%. Management controls restricting the offloading of tour bus passengers was institutes in 1993? has decreased the number of visitors to the bay. click here to see how many visitors Hanauma Bay has received in recent years.

Presently, about 15% of the bay‘s users are Hawai‘i residents and 85% are tourists. In recent years the city has considered charging fees for entry to Hanauma Bay. In response, KSBE has claimed that such fees may violate the original conveyance terms for the Koko Head area.


Ownership of Hanauma Bay and Koko Head District Park transferred from the Bernice Pauahi Bishop Estate to the City and County of Honolulu.  The deed specified the area to be used as public recreational and public access. The Bishop Estate sold the leasehold area for one dollar.


In October of this year, Kalanianaole Highway was opened to the public. This provided a coastal link from Hanauma Bay to Sandy Beach.


The State bus system, Honolulu Rapid Transit (HRT), was extended to include Hanauma Bay. This trial route was established for weekends and holidays only.

A beach access road was constructed by the County Parks Dept. to allow access to the beach for both the public and maintenance crews.

Restrooms, showers and three swimming holes were added during a park improvement project.


The Honolulu Rapid Transit System permanently adds the Hanauma Bay extension route to provide bus service to the park on weekends and holidays.


5-26-1952: Aerial Image of Koko Marina.

5-26-1952: Aerial Image of Koko Marina.

A University of Hawai‘i archaeological survey was conducted. The excavated Hanauma Bay shelter cave revealed remains that suggested this site was used as a fishing shelter in the past.


Public safety and traffic congestion forced the closure of the beach access road. This is later revised due to public outcry, allowing limited access on weekdays from 9:00 am to 3:00 pm. Drop off of camping gear, passengers and recreational equipment were allowed but all vehicles were required to park in the parking lot.


A report by the City Parks Superintendent was released. It stated that 50,000 people annually had used the Bay in each of the years from 1950 to 1956. Prior use had been documented as 8,000 people a year.

A 200 foot wide channel is cut through the coral reef by Hawaiian Dredging to lay the first stage of an underwater telephone cable linking Hawai‘i and the West-Coast. Costs exceed $18,000. The dynamite blasting of the reef and construction equipment forced the closure of the Bay to the public.

In November of this year, construction of the project is completed and Hanauma Bay is reopened for public use.


1-14-1963 Aerial Images of Hanauma Bay and nearby Koko Marina. 1-14-1963 Aerial Images of Hanauma Bay and nearby Koko Marina.
1-14-1963 Aerial Images of Hanauma Bay and nearby Koko Marina.


A proposal to establish a marine sanctuary and underwater park is submitted by the State Fish and Game Division.


The beach concession stand is opened.


In October of this year, Hanauma Bay is officially designated a Marine Life Conservation District by the Board of Land and Natural Resources. The conservation status makes it illegal to fish or remove any marine life or other marine resources from the Bay.

A survey of the fish populations is conducted by the Hawai‘i Cooperative Fisheries Unit.

The Hawai‘i Council of Diving Clubs proposes that the Bay be designated as an underwater park. The proposal includes complete mapping of the Bay and a beach pavilion to display charts of the Bay.


2-8-1968 Aerial Images of Hanauma Bay and Koko Marina. 2-8-1968 Aerial Images of Hanauma Bay and Koko Marina.
2-8-1968 Aerial Images of Hanauma Bay and Koko Marina.

The City Parks Dept. releases plans for erosion control and beach improvement. In November of this year, plans were approved by the State Dept. of Land and Natural Resources, the Dept. of Transportation and the U.S. Army Corp of Engineers. Permits were not issued at this time.


The Division of Aquatic Resources begins conducting fish surveys of the Bay.


Increased concerns of erosion led to speculation by City Officials that beach erosion was caused by wave action attributed to the transpacific cable trench. Plans were made to create a 100 x 15 foot underwater boulder wall to lessen impact to the beach. A new swimming area and a passage through the reef for divers was also planned.

Beach restoration was to be implemented by the addition of 4,000 cubic ft. of sand.

Due to increased concerns of siltation and beach erosion, the City Dept. of Parks and Recreation began the erosion control and park improvement project. The $110,000 project did not obtain the necessary permits to begin the work. The work was started in April but soon halted until permits were secured.

The permit was approved by the Army Corp of Engineers and construction resumed in May.

The Dept. of Land and Natural Resources was appropriated $50,000 by the Legislature for restoration of the Bay.


The Hawai‘i Register of Historic Places places Hanauma Bay Cave Shelter on their list of historic places.


The State‘s Dept. of Land and Natural Resources plans a kiosk, public safety signs and buoys to be installed with Legislature appropriation of $50,000.

Surveys, and mapping of underwater trails are conducted by the University of Hawai‘i‘s Marine Option Program in preparation of underwater guided tours and a specimen showcase.


"The Ocean: Hawai‘i‘s Last Frontier" conference is held in March. Following the suggestion of underwater trail markers suggested at the conference, the City Parks and Recreation Dept. and the Marine Option Program begin basic snorkeling classes and guided underwater tours for a fee in April. Classes and tours are offered daily during the summer.


The kiosk display featuring marine life in Hanauma Bay is installed by the State Parks Division.


The Hanauma Bay Beach Park Site Development Plan and Report is presented to the City and County of Honolulu‘s Dept. of Parks and Recreation.


1-6-1978: Aerial Images of Hanauma Bay and Koko Marina. 1-6-1978: Aerial Images of Hanauma Bay and Koko Marina.
1-6-1978: Aerial Images of Hanauma Bay and Koko Marina.

A new permit was issued by the Dept. of Parks and Recreation to control use of beach access road by commercial tour operators and the public. The City is absolved of and liability by permit holders. Permit holders may drop off recreational gear only. Passengers are no longer allowed to be dropped off or picked up from beach.


Shuttle service begins to transport passengers from the parking lot to the beach. A five year contract was issued to a concessionaire and all previous contracts with dive tour operators are cancelled.


Increasing numbers of visitors to Hanauma Bay prompt a million dollar park improvement project. Services include drainage, a new access road, parking lot expansion, and picnic areas, landscaping and lighting.


To limit the use of the Bay, the Board of Land and Natural Resources restricts parking stalls to 390 spaces.

Commercial operators agree to limit visitor trips to the Bay on weekends to alleviate overcrowding problems. A total ban is suggested for all commercial activities in the Bay.


In response to DLNR pressure, the City imposes a ban on commercial activity. The Board of Land and Natural Resources fines the City $2,000 for failure to enforce the ban against commercial operators on Conservation Lands in Hanauma Bay.

The City Police Dept. Tactical Operations Division conducts undercover sting operations at the Bay to curtail illegal commercial activity.

A sewage spill in June forces closure of the Bay for 8 days. Periodic cesspool overflow had been occurring with the knowledge of the City.


Commercial operators require permits that they protest are too expensive.

The City‘s $1.4 million dollar project begins in March to construct additional picnic areas, relocate a 200 stall parking lot and second access road and turnaround area for buses and vans.

In April, commercial scuba diving and snorkeling is allowed. The Conservation District use permit restricts the numbers to 130 divers at a time. This number is based on 10% of the City‘s estimated carrying capacity of 1,350 people.

In November, a symposium on Hanauma Bay is held. City officials release use figures. Numbers have increased 10 fold from 1970 to 1981 from 210,000 to 2,000,000 visitors annually.


A concessionaire is award the contract to sell food and rent snorkeling equipment at the pavilion.

The $1.4 million dollar park improvement project is completed and an additional 120 stall parking lot is added.


A permit to conduct hiking tours along the rim of Hanauma Bay is approved by the State Board of Land and Natural Resources. Outdoors Hawai‘i may bring in no more than 15 people and 2 vehicles daily.


Aquamatics proposes to expand shuttle service between Waikīkī hotels and Hanauma Bay.

Public opposition halts a bill proposing parking fees to support additional facilities and employees.

A ten-member task force was developed to make recommendations by the end of the year on the Bay‘s physical and environmental limits. The committee never released any report, findings or proposal.

The Planning Commission reviews plans to renovate existing beachside buildings.


Boats are banned from entering waters of Hanauma Bay. Enforcement is given to DLNR enforcement officers and the Dept. of Transportation Harbors Patrol.

Hypodermic needles are found washed ashore at the southwest corner of the Bay.


A preliminary Master Plan for Koko Head District Park is released to the public.


Regulations enacted that restrict fish feeding to authorized types of fish food.


9-24-1992: Aerial Images of Hanauma Bay and Koko Marina. 9-24-1992: Aerial Images of Hanauma Bay and Koko Marina.
9-24-1992: Aerial Images of Hanauma Bay and Koko Marina.


The City and County of Honolulu banned smoking on the beach at Hanauma Bay.


Entrance fees for non-residents are established.


The architectural firm Group 70, hired by the City and County of Honolulu, unveils improvement plans at the Hawai‘i Kai district board meeting. Plans include relocating all Hanauma Bay parking to the vacated Job Corp site, reinstating the military cable car to the top of Koko crater, a visitors center, snack bars, a trolley system across Kalanianaole Highway to Hanauma Bay, and a topside aquarium exhibit at Hanauma Bay. These are planned to alleviate usage of the bay by distributing visitors to other areas. Mandatory snorkeling introductions will be given to first time users.

Dr. Richard Brock of Sea Grant is hired by the City to conduct a carrying capacity study of Hanauma Bay.

Fish feeding is banned in the bay.

Management Concerns:

Hanauma Bay has experienced very high levels of human use over the past 35 years. Primary impacts have been through fish feeding, trampling of corals, and structural change of the reef through the installation of a submarine cable. Areas of management concern include the impact of visitors on the reef and biota, the impact of fish feeding , and the "carrying capacity" in visitor numbers of the site.

Number of visitors at Hanauma Bay.

Number of visitors at Hanauma Bay.

The figure above is based on headcounts at approximately two hour intervals taken by water safety officers over an eight hour work day. Data is from June 1 to May 31 for each year. Source: Hawai‘i State Data Books (1970-2000). These data may be somewhat unreliable as the counts are not exact and are taken by different water safety officers.

In 1975 68% of visitors were local residents while that percentage in 1990 was 13% (Sano 1990).

Fish Feeding in Hanauma Bay

Information summarized from: Wright, Walter. 1999. Delay in enforcing feeding ban at Hanauma allows more research. Honolulu Advertiser. Thursday, April 29, 1999. Page B1.

On April 28, 1999 the City Council approved funding of a $100,000 study of the park‘s capacity to handle visitors. Dr. Richard Brock of the University of Hawai‘i Sea Grant Program will conduct the research over the coming year. A ban on fish feeding at Hanauma Bay was to become effective on April 15, 1999, but the city and State of Hawai‘i agreed to delay enforcement for approximately 3 months so that Dr. Brock can measure the "before" and "after: effects as part of his study. Aquatic Biologist Alton Miyasaka of the DLNR expects that the following changes will occur when feeding is curtailed:

Fish populations will shift away from nenue (rudder fish) and pualu (surgeonfish) that thrive on artificial food supply and currently dominate the inshore reef.

The nenue and pualu will be replaced by more colorful weke (goatfish), parrotfish, butterflyfish and damselfish.

There may be a decline in numbers of fishes, but reduction in larger fishes may be made up by increases in number of smaller fishes.

Because the change will be gradual, no mass die-offs of any kind are expected. The numbers of eels, which feed on other fish, may also gradually decline.

Human Use Patterns:


The Board of Water Supply services the Hanauma Bay Nature Preserve. Koko Head Reservoir 405 has a capacity of 200,000 gallons and also serves the surrounding Portlock community. A 2,400 foot, 8 inch pipe transects the west ridgeline of the crater.

Electric and telephone lines run overhead down the cliff to the restrooms and concession below. Four public telephones and 9 business phones are located in the beach area. These service the lifeguard stand, the concessions, the visitors center and the caretaker’s house.


Hanauma Bay Preserve contains four restroom buildings. The regional wastewater system is processed at the Hawai‘i Kai Sewage Treatment Plant across from Sandy Beach. Effluent from the plant is discharged through an offshore outfall extending 3,000 feet off Sandy Beach. This secondary sewage treatment is released in 35 feet of water.

Status (Degree of Legal Protection):

Marine Life Conservation District.

Noteworthy Biota or Ecological Conditions

Terrestrial Plants

Two main zones divided the beach park. The surrounding cliffs and ridges have climate typical of island windward regions. Hot and dry with shallow soil prevent the growth of most flora. This region includes the introduced Australian saltbush, Bermuda grass, Kiawe, Koa haole, coconut palms, banyan trees and hialoa. The shoreline region include the halophyllic vegetation tolerant to salt spray like the native ilima, naupaka and pohu‘ehu‘e. Various introduced grasses were planted above the high tide line.

An endemic fern, Marsillea villosa can be found on the flats above the cliff above witches brew. This plant has been placed on the endangered species list. It reproduces only in times of heavy rainfall.


Introduced mice, rats, mongoose, insects and lizards inhabit the area. Common introduced birds include pigeons, mynahs, doves, sparrows and cardinals. Feral cats can also be found in the area.

Economic Value and Social Benefits:

In 1995, the City Council of the City and County of Honolulu passed ordinance 95-36 which placed a $5 admission charge on non-Hawai‘i residents over the age of 13. The ordinance went into effect July 1, 1995.

In 1996 the City Council amended these rules by implementing a voluntary donation system where non-Hawai‘i residents over the age of 13 are now charged $3 to enter the bay and everyone is charged $1 to park in the parking lot above the bay. The ordinance went into effect on April 25, 1996. Parking fees are also charged to tour buses.

In 2003, Hanauma Bay increased the admission fees to $5.

Revenue accrued to the C&CH from Hanauma Bay admission fees, parking fees, and concession sales.

Graph showing the revenue accrued by Hanauma Bay.

Graph showing the revenue accrued by Hanauma Bay.

Year Admission Fees Parking Fees Concessions Total
FY 1995 $403,000 $403,000
FY 1996 $2,160,736 $275,000 $361,000
FY 1997 $769,765  $76,299 $372,000
FY 1998 $2,480,446 $244,072
Admission Fees Parking Fees All concessions
FY 2003 $1,911,048 $188,252 $337,209
FY 2004 $2,213,703 $244,788 $768,970
FY 2005




Role of this site in the CRAMP overall experimental design:

Hanauma Bay has served as a CRAMP proving ground for experimental coral reef monitoring methods.

CRAMP sites: specific locations:





Location Line-ups





inside reef on witches brew side





outside toilet bowls





middle bay





witches brew

Study Site Summary of Results


Last Update: 02/24/2011

By: Dan Lager

Hawai‘i  Coral Reef Assessment & Monitoring Program

Hawai‘i  Institute of Marine Biology

P.O. Box 1346

Kāne‘ohe, HI 96744

808-236-7440 phone

808-236-7443 fax